The present invention relates to a saddle-ride type vehicle comprising a clutch assembly (4), interposed between an engine (2) and a gearbox (3), which includes a clutch device (11) in turn comprising two clutch elements (one integral with the shaft of the engine and the other with the input shaft of the gearbox) and return means (12) that keep these elements (11A, 11B) in contact in a closure condition of the clutch. According to the invention, the clutch assembly (4) further comprises an operating device (21) of the clutch device that causes detachment of the elements (11A, 11B) of the clutch device up to an opening condition of the clutch assembly. This latter further comprises a control device (6) to limit the torque peaks during gear change. This device comprises an actuation means (5) that, during gear change, exerts a predetermined force (S) in contrast to the force exerted by said return means (12) of the clutch assembly, wherein said predetermined force (S) is less than the force (F) generated by the return means (12) so as to cause a mutual slip of the elements (11A, 11B) of the clutch device (11) without said opening condition being reached. The operating device (21) is of hydraulic type and comprises a primary pump (22) operated by means of a control lever (23), wherein this primary pump (22) is hydraulically connected, through a primary hydraulic circuit (16), to a primary piston (24) acting on at least one of the elements (11A, 11B) of the clutch device (11) in opposition to the return means (12) so that, following an action on the control lever (23), the primary piston (24) exerts an action the elements (11A, 11B) determining the opening condition. According to the invention, the control device (6) comprises a secondary piston (25) connected to the primary piston (24), wherein the actuation means (5) exerts, directly or indirectly, the predetermined force (S) on the secondary piston (25), said predetermined force (S) being transferred to the primary piston (24) in opposition to the force (F) of the return means (12).

A control apparatus of an all-wheel drive vehicle includes a vehicle speed detector, a first clutch, a second clutch, and a clutch controller. The vehicle speed detector detects a speed of the all-wheel drive vehicle. The first clutch is provided between a parking mechanism and a drive force source of the all-wheel drive vehicle, and adjusts first drive force to be transmitted from the drive force source to an output shaft of an automatic transmission of the all-wheel drive vehicle. The second clutch is provided between the parking mechanism and a drive wheel of the all-wheel drive vehicle, and adjusts second drive force to be transmitted from the output shaft to the drive wheel. The clutch controller controls engagement force of the first and second clutches, and disengages the first and second clutches when the speed of the all-wheel drive vehicle is equal to or less than a predetermined speed.

A clutch apparatus includes a clutch hub, a clutch drum, a multi-plate clutch having inner clutch plates and outer clutch plates, a piston for pressing the multi-plate clutch, an electric motor, a moving mechanism for moving the piston in an axial direction in accordance with the amount of rotation of the electric motor, and a control unit for controlling the electric motor. When increasing a rotational force that is transmitted between the clutch hub and the clutch drum by increasing electric current that is supplied to the electric motor, the control unit moves the piston in the axial direction by temporarily supplying the electric motor with the electric current having a first current value that is greater than a second current value corresponding to a target rotational force that needs to be transmitted between the clutch hub and the clutch drum.

A method for synchronizing a first drive element rotatable about an axis of rotation with a second drive element rotating about the axis of rotation at a target speed, of a powertrain of a motor vehicle, in which a synchronizing force is exerted on a synchronizing unit by an actuator. A speed, at which the first drive element rotates about the axis of rotation is adapted by the synchronizing unit to the target speed. The synchronizing force is increased during a first time span, so that the speed approaches the target speed. The synchronizing force is continuously reduced during a second time span following the first time span, before the speed corresponds to the target speed.

A vehicle includes a drive source, driving wheels driven by a driving force output from the drive source, a clutch disposed between the drive source and the driving wheels, the clutch being switchable to an arbitrary fastening position between a connection state that enables transmission of the driving force between the drive source and the driving wheels and a disconnection state that disconnects the transmission; a clutch actuator that applies a fastening load to the clutch and provides a torque transmission capacity corresponding to the fastening load to the clutch; and a controller that controls operation of the drive source and operation of the clutch actuator. The controller includes a clutch temperature estimation circuit that estimates the temperature of the clutch, and a driving force adjustment circuit that performs driving force adjustment control to adjust the driving force transmitted to the downstream side of the clutch on the basis of the estimated temperature of the clutch.

An AWD-vehicle control device includes a transfer clutch that adjusts a driving force, a detector that detects a steering angle of a steering wheel, a detector that detects an accelerator pedal opening, a detector that detects a vehicle speed, a detector that detects an engine revolution speed, a detector that detects a turbine revolution speed of a torque converter, and a transfer clutch controller that adjusts hydraulic pressure supplied to the transfer clutch and controls a coupling force of the transfer clutch. If a predetermined period has passed from the accelerator pedal opening becoming less than a predetermined opening, the vehicle speed is within a predetermined range, a deviation between the engine and turbine revolution speeds is less than a predetermined speed, and the steering angle is equal to a first predetermined angle or greater, the transfer clutch controller controls the hydraulic pressure to reduce the coupling force.

A four-wheel-drive vehicle includes: a pump that is actuated by an electric motor; a friction clutch that has a plurality of clutch plates that are pressed by a piston that is movable by working oil discharged from the pump; a control device that controls the electric motor; front wheels, to which a drive force of an engine is always transferred; and rear wheels, to which the drive force of the engine is transferred in accordance with the fastening force of the friction clutch. When it is determined that the vehicle is in a high fastening force-requiring state in which it is necessary for the friction clutch to transfer a large drive force temporarily, the control device causes the electric motor to output torque that is larger than torque that the electric motor can continuously output.

A clutch apparatus includes a clutch hub, a clutch drum, a multi-plate clutch having inner clutch plates and outer clutch plates, a piston for pressing the multi-plate clutch, an electric motor, a moving mechanism for moving the piston in an axial direction in accordance with the amount of rotation of the electric motor, and a control unit for controlling the electric motor. When increasing a rotational force that is transmitted between the clutch hub and the clutch drum by increasing electric current that is supplied to the electric motor, the control unit moves the piston in the axial direction by temporarily supplying the electric motor with the electric current having a first current value that is greater than a second current value corresponding to a target rotational force that needs to be transmitted between the clutch hub and the clutch drum.

A method to estimate an amount of force in a clutch pack of a clutch actuation system. The method includes engaging an actuation motor to apply a set point force to the clutch pack and monitoring a position of the actuation motor when the set point force is applied. Additionally, the method includes determining one or more clutch clamping curves and one or more clutch releasing curves based on a relationship between the position of the actuation motor and an amount of torque applied by the actuation motor at position of the actuation motor. The method further includes modeling one or more frictional characteristics of the clutch actuation system and estimating an amount of clamping and releasing force within the clutch pack by using a control unit. The amount of torque applied to the clutch pack between the clutch clamping and releasing curves at the set point force is maintained.

An AWD-vehicle control device includes a transfer clutch that adjusts a driving force, a detector that detects a steering angle of a steering wheel, a detector that detects an accelerator pedal opening, a detector that detects a vehicle speed, a detector that detects an engine revolution speed, a detector that detects a turbine revolution speed of a torque converter, and a transfer clutch controller that adjusts hydraulic pressure supplied to the transfer clutch and controls a coupling force of the transfer clutch. If a predetermined period has passed from the accelerator pedal opening becoming less than a predetermined opening, the vehicle speed is within a predetermined range, a deviation between the engine and turbine revolution speeds is less than a predetermined speed, and the steering angle is equal to a first predetermined angle or greater, the transfer clutch controller controls the hydraulic pressure to reduce the coupling force.